DRAFT

National Aeronautics and Space Administration

November • 2010

DRAFT LAunch PRoPuLsion sysTems RoADmAPTechnology Area 01

Paul K. McConnaughey, ChairMark G. FemminineoSyri J. KoelfgenRoger A. LepschRichard M. RyanSteven A. Taylor

DRAFT

This page is intentionally left blank

DRAFT

Table of Contents

Foreword Executive Summary TA01-11. Introduction TA01-21.1. Technical Approach TA01-21.2. Benefits TA01-51.3. Applicability/Traceability to NASA Strategic Goals, AMPM, DRMs, DRAs TA01-61.4. Top Technical Challenges TA01-7

2. Detailed Portfolio Discussion TA01-72.1. Portfolio Summary and Work Breakdown Structure TA01-72.2. Technology Description and Development Details TA01-8

2.2.1. Solid Rocket Propulsion Systems (TABS 1.1) TA01-82.2.2. Liquid Rocket Propulsion Systems (TABS 1.2) TA01-82.2.3. Air-Breathing Propulsion Systems (TABS 1.3) TA01-92.2.4. Ancillary Propulsion Systems (TABS 1.4) TA01-92.2.5. Unconventional/Other Propulsion Systems (TABS 1.5) TA01-92.2.6. Technology Area Roadmaps and Table Descriptions TA01-92.2.6.1. SolidRocketPropulsionSystems TA01-102.2.6.2. LiquidRocketPropulsionSystems TA01-112.2.6.3. Air-BreathingLaunchPropulsionSystems TA01-122.2.6.4. AncillaryPropulsionSystems TA01-132.2.6.5. Unconventional/OtherPropulsionSystems TA01-14

2.2.7. Technology Area Tables TA01-152.2.7.1. SolidRocketPropulsionSystems TA01-152.2.7.2. LiquidRocketPropulsionSystems TA01-162.2.7.3. Air-BreathingLaunchPropulsionSystems TA01-172.2.7.4. AncillaryPropulsionSystems TA01-192.2.7.5. Unconventional/OtherPropulsionSystems TA01-21

3. Interdependency With Other Technology Areas TA01-234. Possible Benefits to Other National Needs TA01-24Acronyms TA01-25Acknowledgements TA01-26

DRAFT

ForewordNASA’s integrated technology roadmap, including both technology pull and technology push strategies, considers a wide range of pathways to advance the nation’s current capabilities. The present state of this effort is documented in NASA’s DRAFT Space Technology Roadmap, an integrated set of fourteen technology area roadmaps, recommending the overall technology investment strategy and prioritization of NASA’s space technology activities. This document presents the DRAFT Technology Area 01 input: Launch Propulsion Systems. NASA developed this DRAFT Space Technology Roadmap for use by the National Research Council (NRC) as an initial point of departure. Through an open process of community engagement, the NRC will gather input, integrate it within the Space Technology Roadmap and provide NASA with recommendations on potential future technology investments. Because it is difficult to predict the wide range of future advances possible in these areas, NASA plans updates to its integrated technology roadmap on a regular basis.

TA01-1DRAFT

oxidizer from the atmosphere and could be part of an integrated system that includes more con-ventional rockets to reach the vacuum of space. Hypersonic air-breathing systems, as demonstrat-ed by X-43 and X-51, are still in the experimental stage. Improvements in ancillary propulsion sys-tems would include the supporting subsystems for conventional propulsion systems, including con-trols and smaller rockets not directly responsible for lift to orbit. Unconventional launch technolo-gies include systems that do not rely solely on on-board energy for launch or that use unique tech-nologies or propellants to create rocket thrust. Included in this area are technologies that are at a very low TRL or that do not map into the other propulsion taxonomies.

Solid rocket motors (SRMs) have many advan-tages over liquid systems such as high-energy den-sity and long-term stability and storability. How-ever several disadvantages limit their applicability, which can be reduced or eliminated by advanc-ing the technology base of SRMs to make them more attractive alternatives to liquid systems. Key disadvantages for SRMs today are lower perfor-mance (Isp), lack of throttling on demand or abil-ity to shut down on command, environmental concerns, and ground operations costs associat-ed with safety issues in handling large solid seg-ments. This roadmap proposes technology invest-ments that address some of these disadvantages, as well as enhance the advantages mentioned above. Key areas for improvement include a green pro-pellant alternative to current oxidizers, advancing the ability to assess damage tolerance limits and detect damage on composite cases, developing do-mestic sources for critical materials used in manu-facturing of SRMs, formulating advanced hybrid fuels to get energy density equal to SRMs, and in-vesting in the fundamental physics of SRM design including analysis and design tools.

Liquid rocket propulsion systems use propel-lants (fuels and oxidizers) that are kept in a liquid state prior to and during flight. The advantages of liquid rocket engines include generally higher Isp and better thrust control (including throttling and restart capability) than solids. Liquid rocket pro-pulsion systems are more operationally complex than solids and require some form of active flow control that introduces additional possibilities for failures. The liquid propulsion roadmap addresses the critical figures of merit by proposing technolo-gy investments in new liquid engine systems, pro-pulsion materials research, high-density impulse and green propellants, and new subsystem mod-

exeCuTive SummarySafe, reliable, and affordable access to low-Earth

(LEO) orbit is necessary for all of the nation’s space endeavors. The Launch Propulsion Systems Technology Area (LPSTA) addresses technologies that enhance existing solid or liquid propulsion technologies or their related ancillary systems or significantly advance the technology readiness lev-el (TRL) of newer systems like air-breathing, un-conventional, and other launch technologies. The LPSTA consulted previous NASA, other govern-ment agencies, and industry studies and plans for necessary technology developments, as well as subject matter experts to validate our assessment of this field, which has fundamental technologi-cal and strategic impacts on the nation’s space ca-pabilities.

The LPSTA selected its most promising tech-nologies based on critical figures of merit, in-cluding propulsion system production and op-erational costs, game-changing operational and performance capabilities, and national needs also identified by other government agencies and in-dustry. The technologies reflect the future launch needs of the NASA mission directorates, oth-er government agencies, and commercial indus-try, which include a wide range of payload classes, from small (<2 metric tons (t)) to >50 t.

The LPSTA identified a number of challeng-es across the range of possible launch propulsion technologies to be developed over the next 20 years. These technologies were prioritized based on an LPSTA team consensus for the identified needs and the expected return on investment for each technology area. In the near term, this in-cludes tactical needs like high-strength oxygen-compatible materials for new hydrocarbon-based engines as well as more exotic technologies like launch assist approaches and fusion-powered nu-clear thermal rockets (NTRs).

The LPSTA was organized around five primary technology areas: solid rocket propulsion systems; liquid rocket propulsion systems; air-breathing launch propulsion systems; ancillary propulsion systems, which include subsystems for existing systems, as well as smaller rocket systems like RCS and abort systems; and unconventional and other propulsion systems. Solid and liquid rocket pro-pulsion systems have been used since the dawn of space flight, and naturally comprise fuel and oxi-dizers in solid or liquid form. These technologies are reaching the limits of theoretical efficiency and performance using conventional propellants. Air-breathing launch propulsion systems extract their

TA01-2 DRAFT

eling and design tools. Air-breathing launch propulsion systems obtain

the oxidizer for combustion from the Earth’s at-mosphere, which is combined with fuel brought on board. Air-breathing engines change modes as speed and altitude increases, and transition to pure rocket mode at high altitudes for the final ascent to space. This roadmap focuses on key technolo-gies that would advance air-breathing launch pro-pulsion systems during validation flight tests and would lead to the design of a staged air-breathing launch vehicle. These technology investments in-clude the development of Mach 4+ turbines for turbine-based combined cycles, long-duration Mach 7+ scramjet operation, stable mode transi-tions of rocket-based and turbine-based combined cycle vehicles, an integrated air collection and en-richment system, and detonation wave engine op-eration.

Ancillary propulsion systems that support the main vehicle propulsion system or provide oth-er key launch vehicle functions during ascent, are significant drivers in vehicle cost, complexity, and reliability. Development of new low-cost cryo-genic and rocket propellant (RP) valves, lines and support components is essential to support less ex-pensive new vehicle development and reinvigorate our nation’s technology base in this area. Some ca-pabilities that are within reach with up-front tech-nology development include nontoxic reaction control systems, advanced sensors coupled with smart control systems providing robust integrat-ed vehicle health management (IVHM), high-powered electromechanical actuators (EMAs) and their supporting power supply and distribution systems, large robust mechanical separation sys-tems, and launch abort systems with high-thrust steerable motors tied to an adaptive flight control system. Once developed, these capabilities would have immediate positive impact on vehicle pro-duction and operational costs, overall vehicle reli-ability, and ground and flight safety.

Unconventional and other propulsion systems include near-, mid-, and far-term technology ap-proaches primarily focused on reducing the cost of access to space. Ground-based, hypervelocity ac-celerators for low-cost delivery of large numbers of small, high-g tolerant payloads to LEO are a near-term technology that can provide significant payoff for a relatively small technology invest-ment. Orbiting space tethers that can act as the final stage of a launch system and relieve the per-formance requirements for vehicle ascent, poten-tially enabling fully-reusable, suborbital vehicles

with robust operating margins at current technol-ogy levels, are a promising technology of interest in the mid term. Mid- to far-term technologies that can provide breakthrough improvements in propulsion efficiency through the application of energy generated by means other than chemical combustion, such as power beaming, nuclear fu-sion, and high-energy density materials, are prime candidates for future investment.

The LPSTA roadmap (Fig. 1) reflects a staged development of critical technologies that include both “pull” technologies that are driven by known short- or long-term agency mission milestones, as well as “push” technologies that generate new performance or mission capabilities over the next 20 to 25 years. While solid and liquid propulsion systems are reaching the theoretical limits of ef-ficiency, they have known operational and cost challenges while continuing to meet critical na-tional needs. Improvements in these launch pro-pulsion systems and their ancillary systems will help maintain the nation’s historic leadership role in space launch capability. Newer technologies like air-breathing launch propulsion, unconven-tional, and other propulsion technologies and sys-tems, while low in TRL, can radically transform the nation’s space operations and mission capabil-ities and can keep the nation’s aerospace industri-al base on the leading edge of launch technologies.

1. inTroduCTion

1.1. Technical approachReliable and cost-effective access to space is a

fundamental capability required for all of NASA’s in-space missions. In light of this, NASA’s Of-fice of the Chief Technologist (OCT) has identi-fied the Launch Propulsion Systems Technology Area (LPSTA) to highlight current and poten-tial technology investments by the Agency. In this planning, Earth-to-orbit (ETO) transportation was considered, as other OCT technology areas (TAs) addressed beyond-low-Earth orbit (LEO) transportation. Also, the domain of this plan-ning activity was limited to ETO propulsion sys-tems; other technologies, which could apply to a launch vehicle, e.g., materials, structures, ther-mal, and ground systems, were addressed by other TA teams. This LPSTA was then subdivided into five areas of emphasis, which included (1) solid rocket propulsion systems, (2) liquid rocket pro-pulsion systems, (3) air-breathing launch propul-sion systems, (4) ancillary propulsion systems, and (5) unconventional or other propulsion systems.

TA01–3/4

Figure 1: Launch Propulsion Systems Technology Area Strategic Roadmap (TASR).

DRAFT

This page is intentionally left blank

TA01-5DRAFT

These five areas of emphasis highlight both the current and future challenges for launch propul-sion technology. Much of the work performed in the last 50 years has been through solid and liquid rocket propulsion technologies, which although nearing the theoretical limits of chemical com-bustion performance and efficiency, are still not as cost effective as desired. Technology develop-ments in these areas tend toward enhancing exist-ing capabilities. Other methods of reaching LEO are still at a low technology readiness level (TRL), with some being to the point of being quite theo-retical in nature and concept. Therefore, the tech-nologies needed to enable these new approaches are more diverse and fundamental. Targeted areas for improvement (lowering costs of current sys-tems and maturing low TRL approaches) could benefit significantly from a prudent and balanced technology investment strategy.

To adequately survey the landscape of neces-sary technologies, the LPSTA team reviewed tech-nology assessments and roadmaps developed by NASA, and other organizations over the past 15 years (a total of 16 major technology databases as seen in Table 1); consulted with experts in the fields of solid, liquid, air-breathing, ancillary, and unconventional launch propulsion technologies; and conducted fact-finding discussions with eight aerospace companies to get their inputs on indus-try needs and plans. Because there has been no significant investment or broad-based planning by

NASA in launch propulsion technologies over the last 7 years, the LPSTA roadmap presents signifi-cant updates to planning launch propulsion tech-nologies over a wide range of TRLs and approach-es.1.2. Benefits

The overall goals of LPSTA investments within NASA are to make access to space (LEO) more re-liable, routine, and cost effective. The most com-mon metric used to assess the latter is dollars per kilogram ($/kg) to LEO; other metrics consid-ered in many of the joint NASA planning activ-ities with other governmental agencies addressed short call-up time, launch vehicle turn-around time, sortie rate, and reduced weather constraints. Due to NASA’s need for lower costs as opposed to the operationally responsive requirements, the LPSTA identified technologies with the following characteristics that could significantly lower dol-lars per kilogram to LEO based on the following

• Space Launch Initiative (SLI) Technology Data

• National Aerospace Initiative (NAI) Roadmaps

• Next-Generation Launch Technology (NGLT) Plan

• Advanced Planning and Integration Office (APIO) In-Space Transportation Roadmap

• Integrated High-Payoff Rocket Propulsion Technology (IHPRPT) Plan

• Capability, Requirements, Analysis, and Integration (CRAI) Database

• Alternate Horizontal Launch Space Access Technology Roadmap

• Boeing National Institute of Aerospace (NIA) Hypersonics Report

• NASA Fundamental Aeronautics Program Hypersonics Project 6-Month and 12-Month Reviews (with roadmaps)

• “USA Fundamental Hypersonics” presentation to 16th AIAA/DLR/DGLR International Space Planes and Hypersonic Systems and Technologies Conference

• National Aeronautics Research and Development Plan

• Report to Congress: Roadmap for the High-Speed and Hypersonic Programs

• National Hypersonics Plan: Access to Space Team Roadmap

• Gryphon Integrated Product Team (IPT) Kickoff Meeting and Roadmap

• NASA Hypersonics Project Planning Meeting• National Research Council (NRC) Decadal

Survey of Civil Aeronautics

Table 1. Databases Consulted by LPSTA.

Propulsion system production costs

Propulsion system operational costs

Game-changing system & operational conceptsGame-changing propulsion system /subsystem efficiency and capabilityNational needs supported by input from other government agencies and industry

TA01-6 DRAFT

figures of merit:The overall goal of these technologies would be

to reduce launch costs by 25–50 percent over the next 20 years, with a higher reduction (>50%) ex-pected for non-conventional and innovative con-cepts. It is expected that the most feasible path to achieve this goal is to develop launch systems with reusable elements that reduce operational and re-curring hardware costs. This reduction could be achieved with significant incremental improve-ments in current systems or approaches, e.g., a re-usable booster system. Similar benefits could result from launch assist or air-drop systems. Addition-al cost reductions and performance gains should come from either air-breathing or non-conven-tional approaches that would carry fuel on board and use ambient air as the oxidizer. These sys-tems, using existing aviation infrastructure such as airports, runways, and jet engines, could pro-duce much higher flight rates over a broader azi-muth capability than rocket-based systems. High-er flight rates measured in hours instead of days, weeks, or months make missions requiring mul-tiple launches or payloads much more feasible. To achieve these “airline like” operations, design teams have typically looked at applications of ad-vanced air-breathing systems, with a focus on the hypersonic flight regime.

The challenge for all launch propulsion systems is that the performance requirements dictated by the physics of escaping Earth’s gravity leave very little margin in the systems to find existing tech-nology solutions that reduce cost, enhance reli-ability, or improve operability. Whether based on conventional liquid or solid based designs, or on a hypersonic boost approach, systems to date have not exhibited the performance, design, and life margins that lead to operational robustness. A true breakthrough in space access will require con-cepts that produce significant increases in system margins while still providing a high level of per-formance.

However, at present solid and liquid rocket-based propulsion systems remain the primary means for the U.S. to launch payloads to LEO. Given the nation’s near-term dependence on space-based as-sets in LEO and other orbits, it is vital that the na-tion maintains its industrial capability to design, build, test, and fly updated and new solid and liq-uid rockets. National-level investments in tech-nologies to support these systems will remain wise investments for the foreseeable future. This is con-sistent with a major finding from the LPSTA in-dustry discussions, where the team identified the

need to improve the United States’ leadership in aerospace technology, independence from foreign sources of technology or materials, and the need to maintain a basic and consistent investment in launch propulsion system technologies and capa-bilities.1.3. applicability/Traceability to naSa

Strategic Goals, amPm, drms, drasTo develop a responsive set of technology goals

and applicable mission manifest, as well as identi-fy both “push” and “pull” technologies, the LPS-TA team reviewed the National Space Policy, the NASA Draft Strategic Goals, and the draft Agen-cy Mission Planning Manifest for 2011. The team also assessed the technology and implementation plans of NASA’s mission directorates, including the Science Mission Directorate (SMD), Space Operations Mission Directorate (SOMD), the Ex-ploration Systems Mission Directorate (ESMD, and the Aeronautics Research Mission Directorate (ARMD). In addition to these plans and goals, the team utilized the findings of the Human Explora-tion Framework Team (HEFT), which generated design reference missions (DRMs) in response to the proposed 2011 President’s budget for NASA, and the results of the Agency Study Teams, which formulated initial responses to the Office of Man-agement and Budget (OMB) budget guidance for 2011. The latter includes the Heavy-Lift Propul-sion Technology (HLPT) plan and the Commer-cial Crew Development (CCDev) plan.

Results of this assessment are seen in the mis-sion manifest depicted in the integrated LPSTA roadmap in Figure 1 of the Executive Summary. For the SMD missions, launch vehicle require-ments result in a steady tempo of launches, com-prising 5–8 payload launch requirements per year. The payload class ranges of these requirements in-clude 3 to 4 small (<2 t) payloads per year, 2 to 3 medium (2–20 t) payloads per year, and a heavy (20–50 t) payload requirement every few years. As a customer of launch services, SMD depends on national capabilities and does not invest in launch propulsion system technologies; it is primarily in-terested in low-cost and reliable launch services. ESMD has a significant proposed investment in LPSTA; this can be seen in the HLPT plan and its emphasis on selected engine technologies, e.g., RP and methane (CH4) prototype engines. It is also reflected in the HEFT planning to support a near-Earth object (NEO) mission (the require-ment for a crewed super-heavy (>50 t) launch ve-hicle in the 2020 time frame), and in the funding

TA01-7DRAFT

of CCDev for low-cost, conventional launch pro-pulsion technologies by 2015. ARMD planning includes regular efforts in hypersonic tests and technologies. These tests are critical for develop-ing efficient hypersonic capabilities that support access to space for small- and medium-class pay-loads, as these hypersonic air-breathing vehicles could be used as a first-stage booster for an upper-stage and payload. OCT’s investment in LPSTA is still to be determined, and this LPSTA roadmap provides an initial plan with options and candi-dates for future NASA technology funding.

Reflecting the mission requirements and the technology plans of the Agency, the LPSTA team developed a representative launch vehicle manifest (seen in the second row of Fig. 1), with launch ve-hicles categorized as:

These vehicle classes were used to generate rep-resentative vehicle systems that supported mission requirements. Launch propulsion technologies

were then mapped to these vehicle systems. An additional category was included for flight tests of new launch vehicles, i.e., air-breathing launch propulsion.1.4. Top Technical Challenges

LPSTA identified major technical challenges for three time horizons, which reflect the needs and expected successes in the near (present to 2016), mid- (2017–2022), and long-term (2023–2028) time frames. These technologies were prioritized within each phase based on an LPSTA team con-sensus for both the identified needs and the ex-pected ROI for each technology area. This result-ed in a balance of challenges that address problems

with operation and cost of current systems while establishing research in the non-conventional sys-tems. Each of the technology challenges seen in Table 2 will be discussed in more detail in Section 2 of this roadmap report.

2. deTailed PorTFolio diSCuSSion

2.1. Portfolio Summary and work Breakdown Structure

The LPSTA team assembled a work breakdown structure, referred to here as the Technology Area Breakdown Structure (TABS) to organize the technologies described in this section. This TABS, shown in Figure 2, concentrates on engines, mo-tors, and other technologies capable of lifting pay-loads from the Earth’s surface to LEO, as well as their associated propulsion-supporting subsys-tems. The top-level content represents a taxono-my based on the primary characteristics of pro-pulsion systems, and they differ in their range of technical and operational maturity. Chemical sol-id and liquid rocket propulsion systems have been used since the dawn of space flight, and as their names suggest, consist of fuel and oxidizers in sol-id or liquid form. These technologies (as current-ly used on the Space Shuttle and other vehicles) are reaching the limits of theoretical efficiency and performance using conventional propellants. Air-breathing launch propulsion systems extract their oxidizer from the atmosphere and could be part of an integrated system that includes more con-ventional rockets to reach the vacuum of space. Hypersonic air-breathing systems, as demonstrat-ed by X-43 and X-51, are still in the experimental stage. Improvements in ancillary propulsion sys-tems would include the supporting subsystems for conventional propulsion systems, including con-trols and smaller rockets not directly responsible for lift to orbit. Unconventional launch technolo-gies include systems that do not rely solely on on-board energy for launch or that use unique tech-

Small: 0–2 t payloadsMedium: 2–20 t payloadsHeavy: 20–50 t payloadsSuper Heavy: > 50 t payloads

Present – 2016 2016 – 2022 2023 – 2028

1. High-Strength Oxygen-Compatible Materials 1. Large ORSC Engine 1. Hypersonic Technology Validation Flight

2. Integrated Ramjet/Scramjet Flight to Mach 7+ 2. ACES Integrated Flight System 2. High Energy Density Propellants

3. SRM Composite Case Damage Tolerance and Detectability

3. RBCC/TBCC Mode Transition 3. SRM Green Propellant

4. Nontoxic RCS 4. Advanced Expander Cycle Engine 4. Advanced Alt. Liquid Fuels

5. Advanced RP and Cryogenic MPS Components 5. MHD-Augmented Rocket 5. Nuclear Fusion NTR

6. TBCC Mach 4+ Turbine Acceleration 6. Large Scale, High Volumetric Efficiency Hybrid (1Mlbf Thrust.)

7. Hypervelocity Accelerators 7. Power Beaming Technologies and Propulsion Systems

8. Carbon-Carbon Nozzle (Domestic Source)

Table 2. Top Technical Challenges by Time Frame.

TA01-8 DRAFT

nologies or propellants to create rocket thrust. Included in this area are technologies that are at a very low TRL or that do not map into the oth-er propulsion taxonomies. The technology area breakdown structure that focuses on these five ar-eas can be seen in Figure 2.2.2. Technology description and

development details2.2.1. SolidRocketPropulsionSystems

(TABS1.1)Solid rocket motors (SRMs) have many ad-

vantages over liquid systems such as high-ener-gy density and long-term stability and storabili-ty. However several disadvantages that limit their applicability can be reduced or eliminated by ad-vancing the technology base of SRMs to make them more attractive alternatives to liquid sys-tems. Key disadvantages for SRMs today are low-er performance (Isp), lack of throttling on demand or ability to shut down on command, environ-mental concerns, and ground operations costs as-sociated with safety issues in handling large solid segments. This roadmap proposes technology in-vestments that address some of these disadvantag-es, as well as enhance the advantages mentioned

above. Key areas for improvement include a green propellant alternative to current oxidizers, ad-vancing the ability to assess damage tolerance lim-its and detect damage on composite cases; devel-oping domestic sources for critical materials used in manufacturing of SRMs, formulating advanced hybrid fuels to get energy density equal to SRMs, and investing in the fundamental physics of SRM design including analysis and design tools.2.2.2. LiquidRocketPropulsionSystems

(TABS1.2)Liquid rocket propulsion systems use propel-

lants (fuels and oxidizers) that are kept in a liquid state prior to and during flight. The advantages of liquid rocket engines include generally higher Isp and better thrust control (including throttling and restart capability) than solids. Liquid rocket pro-pulsion systems are more operationally complex than solids and require some form of active flow control that introduces additional possibilities for failures. The liquid propulsion roadmap addresses the critical figures of merit by proposing technolo-gy investments in new liquid engine systems, pro-pulsion materials research, high-density impulse and green propellants, and new subsystem mod-eling and design tools.

Figure 2. Technology Area Breakdown Structure technology areas for launch propulsion.

TA01-9DRAFT

2.2.3. Air-BreathingPropulsionSystems(TABS1.3)

Air-breathing launch propulsion systems obtain the oxidizer for combustion from the Earth’s at-mosphere, which is combined with fuel brought on board. Air-breathing engines change modes as speed and altitude increases, and transition to pure rocket mode at high altitudes for the final ascent to space. This roadmap focuses on key technolo-gies that would advance air-breathing launch pro-pulsion systems during validation flight tests and would lead to the design of a staged air-breathing launch vehicle. These technology investments in-clude the development of Mach 4+ turbines for turbine-based combined cycles, long-duration Mach 7+ scramjet operation, stable mode transi-tions of rocket-based and turbine-based combined cycle vehicles, an integrated air collection and en-richment system, and detonation wave engine op-eration.2.2.4. AncillaryPropulsionSystems

(TABS1.4)Ancillary propulsion systems that support the

main vehicle propulsion system or provide oth-er key launch vehicle functions during ascent, are significant drivers in vehicle cost, complexity, and reliability. Development of new low-cost cryogen-ic and rocket propulsion (RP) valves, lines, and support components is essential to support less ex-pensive new vehicle development and reinvigorate our nation’s technology base in this area. Some ca-pabilities that are within reach with up-front tech-nology development include nontoxic reaction control systems, advanced sensors coupled with smart control systems providing robust integrat-ed vehicle health management (IVHM), high-powered electromechanical actuators (EMAs) and

their supporting power supply and distribution systems, large robust mechanical separation sys-tems, and launch abort systems with high thrust steerable motors tied to an adaptive flight control system. These capabilities, once developed, would have immediate positive impact on vehicle pro-duction and operational costs, overall vehicle reli-ability, and ground and flight safety.2.2.5. Unconventional/OtherPropulsion

Systems(TABS1.5)Unconventional and other propulsion systems

include near, mid, and far-term technology ap-proaches primarily focused on reducing the cost of access to space. Ground-based, hypervelocity accelerators for low-cost delivery of large numbers of small, high-g tolerant payloads to LEO are a near-term technology that can provide significant payoff for a relatively small technology invest-ment. Orbiting space tethers that can act as the final stage of a launch system and relieve the per-formance requirements for vehicle ascent, poten-tially enabling fully-reusable, suborbital vehicles with robust operating margins at current technol-ogy levels, are a promising technology of interest in the mid-term. In the mid to far term, technolo-gies that can provide breakthrough improvements in propulsion efficiency through the application of energy generated by means other than chemical combustion, such as power beaming, nuclear fu-sion, and high-energy density materials, are prime candidates for future investment.2.2.6. TechnologyAreaRoadmapsand

TableDescriptionsThe LPSTA technology tables identify figures of

merit and payload launch classes addressed.Production cost improvements would include

reducing vehicle manufacturing costs. Opera-

Propulsion system production costs Small: 0–2 t payloads

Propulsion system operational costs Medium: 2–20 t payloads

Game-changing system and operational concepts

Heavy: 20–50 t payloads

Game-changing propulsion system/ sub-system efficiency and capability

Super Heavy: > 50 t payloads

National needs supported by input from other government agencies and industry

Flight tests of new launch vehicles, e.g., air-breathing launch propulsion

TA01-10 DRAFT

tional cost improvements would include reducing personnel or infrastructure costs. Game-changing system and operational concepts broadly expand space activities via higher mass or flight frequency. Game-changing efficiency and capability advances include improving individual vehicle or subsystem performance for more robust operations. National

needs supported by input from other government agencies and industry help multiple government or industry partners.2.2.6.1. Solid Rocket Propulsion Systems

Figu

re 3

. Sol

id R

ocke

t Pro

pulsi

on S

yste

ms T

echn

olog

y Roa

dmap

.

TA01-11DRAFT

2.2.6.2. Liquid Rocket Propulsion Systems

Figu

re 4

. Liq

uid

Rock

et P

ropu

lsion

Sys

tem

s Tec

hnol

ogy R

oadm

ap.

TA01-12 DRAFT

2.2.6.3. Air-Breathing Launch Propulsion Systems

Figu

re 5

. Air-

Brea

thin

g Pr

opul

sion

Syste

ms T

echn

olog

y Roa

dmap

.

TA01-13DRAFT

2.2.6.4. Ancillary Propulsion Systems

Figu

re 6

. Anc

illar

y Pro

pulsi

on S

yste

m R

oadm

ap.

TA01-14 DRAFT

2.2.6.5. Unconventional/Other Propulsion Systems

Figu

re 7

. Unc

onve

ntio

nal/O

ther

Lau

nch

Tech

nolo

gy R

oadm

ap.

TA01-15DRAFT

2.2.7. TechnologyAreaTables2.2.7.1. Solid Rocket Propulsion Systems

Technology investment description Trl major Challenges Path to Trl6

1.1.1 Propellants – New formulations for improved performance, environmental impact, and manufacturing processing

HTPB Large Batch Mix/Pour Demo

Scale up HTPB production to a 1,800-gal propellant mix to pour into a full-scale load test motor steel case 4-segment demonstra-tor.

4 Developing prebatch techniques that allow a full segment to be cast (approx. 13–15 mixes per segment).

Develop mix cycles at smaller scales, adapt a shorter mix cycle to a 1,800-gal-lon mixer, make several demonstration mixes using shorter mix cycle, evaluate data from test articles, and demonstrate effectiveness in full-scale motor firing.

HTPB Continuous Mix/Pour Demo

Scale up to continuous mix with full-scale 4-segment steel case load test motor steel case demonstrator. Demonstrate quality assurance for new process to apply to human rated systems.

3 Need large-scale continuous mix facility, need mix process.

Demonstrate continuous mix process on smaller scale, build large-scale mix facility, cast smaller motor using large continuous mix process, evaluate data from test articles, demonstrate in full-scale motor firing.

AP Replacement Research

Fundamental research into alterna-tive high-energy solid propellants that can replace the current AP used in today’s motors.

2–3 Find replacement for ammonium perchlorate (AP) that has adequate energy, density, & stability.

Literature search, lab work, subscale test-ing, large-scale testing.

High-Energy Density Green Propellant Demo

Develop subscale demonstrations of promising candidates.

1–2 Need AP replacement (see above) and high-energy density ingredi-ents.

Develop propellant using AP replace-ment (see above) and high-energy den-sity ingredients, demonstrate in full-scale motor firing.

1.1.2 Case Materials – Advanced case materials development, damage detection and repair techniques, handling process development to mitigate damage to large composite cases

Composite Case Damage Tolerance & Detectability

Develop damage tolerance limits and methods for detecting damage in large composite motor cases.

3 Detecting structural damage in the fiber structure of composite cases.

Evaluate alternative damage tolerance detection methods and assess against representative damage samples, test against full-scale hardware, qualify processes for flight application.

Large Composite Case Operations and Handling Demo

Develop and demonstrate technol-ogy for handling and operations processing of large composite cases.

3 Moving and handling large compos-ite structures without damaging the composite structure.

Assess risks in handling operations for large composite cases, evaluate solutions for minimizing/eliminating risks, dem-onstrate solutions in full=scale hardware demonstration.

1.1.3 Nozzle Systems – Advanced lightweight ablative materials, alternative nozzle designs

Lightweight, Low-Erosion Nozzle Material Demonstration

Develop and demonstrate new ad-vanced lightweight ablative nozzle materials for solid motors.

2–3 Formulation of new lightweight materials.

Research alternative materials.Evaluate candidates in subscale test rig. Select most likely candidates for testing in large-scale demonstration.

1.1.4 Hybrid Rocket Propulsion Systems – High Propellant density material development with improved burn rate, combustion stability characterization/design parameter understanding, upper stage multiburn motor

High Volumetric Hybrid Propellant Technol-ogy Maturation (fuel/oxidizer/additives web design work)

Hybrid motors do not have the de-sired volumetric efficiency of solid motors. Develop and demonstrate advanced propellant formulations and packaging concepts to im-prove hybrid volumetric efficiency.

2–3 Fuel regression rates are typically ~10 times less for hybrids compared to solids, with baseline HTPB fuels. Need to examine burn rate additives or paraffin or different oxidizer flows or multiport multilayer configura-tions.

Evaluate alternatives, test candidate sub-scale, test most promising alternatives in large scale, develop scaling parameters, demonstrate at 250,000 lbf and 1 Mlbf thrust size motors.

Upper-Stage Variable Thrust/Multiburn Motor

Hybrids can be used for upper-stage variable thrust/multiple-burn applications. Currently selected for use on Sierra Nevada’s Dream Chaser vehicle.

3 Multiple-use components will be a large issue; getting sustained programmable impulse out of the motor is another large issue.

For representative missions/applications/ requirements, perform system studies and develop candidate component solu-tions that can be used and then reused multiple times, test at subscale and full scale as an integrated system.

1.1.5 Fundamental Solid Propulsion Technologies – Advanced design analysis tool development, validation through subscale solid test bed and cold flow testing

Physics Based Model-ing Development and Research

A combination of computational fluid dynamics (CFD) and analytical computation tools must continu-ally be improved to advance the state of the art in designing and analyzing solid rocket motors. Vali-dating these tools requires a robust cold flow and small-scale solids test program.

N/A A consistent level of funding over multiple years is required to develop and execute the test plans necessary to more fully understand the subtle physics underlying SRM perfor-mance.

Validating key physical models will lead to improved prediction and analysis capability. For example erosive burning, which is currently treated as a liability, could be used to increase the perfor-mance of an SRM. Time scales of when the models will be brought online are hard to predict, but if nothing is done, the models will not improve on their own.

Table 3. Solid Rocket Propulsion System Technology Investments.

TA01-16 DRAFT

2.2.7.2. Liquid Rocket Propulsion SystemsTable 4. Liquid Rocket Propulsion System Technology Investments.

Technology invest-ment

description Trl major Challenges Path to Trl6

1.2.1 LH2/LOX Engines – High Isp, liquid hydrogen/liquid oxygen based engines for first or upper-stage propulsion

J-2X Upper stage engine for Constella-tion Program

5 Nozzle extension materials and manufacturing

Development testing (to begin early 2011)

SSME (RS-25) Derivatives Expendable derivative (RS-25E)Upper stage for heavy-lift vehicleExpendable derivative (RS-25F)

534

Manufacturing processes and materialsIntegrated system interactionsManufacturing processes and materials

Full-scale development testing of new components

Common Upper Stage Engine

Common upper-stage expander cycle engine for EELV.

4 Manufacturing processesMaterials

Subscale demonstrators, full-scale development

High Reusability Engine Low-cost, high-reliability engine 3–4 Manufacturing processesMaterials

Modeling of systems, subscale demon-strators, full-scale development

1.2.2 RP/LOX Engines – High energy density kerosene-based engines for first stage lift

Large Hydrocarbon Engine

High-thrust booster engine 3–4 Manufacturing ProcessesMaterialsCombustion instability

Modeling of systems, subscale demon-strators, full-scale development

High Reusability Engine Low-cost, high-reliability engine 2–3 Manufacturing ProcessesMaterials

Modeling of systems, subscale demon-strators, full-scale development

1.2.3 CH4 Engines – Alternative hydrocarbon engines with high energy density and Isp

Methane Upper-Stage Engine

Development of technologies to support high-altitude start and operation of LOX/CH4 engine

3 IgnitionManufacturing processesMaterials

Subscale demonstrator, full-scale dem-onstrators

Methane Booster Engine Development of technologies to support operation of LOX/CH4 engine.

3 IgnitionManufacturing ProcessesMaterials

Subscale demonstrators, full-scale demonstrators

1.2.4 Detonation Wave Engines (Closed Cycle) – produce thrust by igniting fuel and oxidizer through a series of controlled detonation waves

Closed Cycle Detonation Wave Engine

Detonation wave engines produce thrust by igniting fuel and oxi-dizer through a series of controlled detonation waves. In a closed cycle oxidizer is supplied by the vehicle.

3 IgnitionManufacturing processesMaterialsCooling

Modeling of systems, subscale demon-strators, full-scale demonstrators

1.2.5 Propellants – Propellant research involves application of nontoxic green propellants, high-energy combinations of fuels and oxidizers

Propellant Densification Propellant densification delivers enhanced vehicle mass fraction performance

5 LOX4–5 LH2

Ground Support Equipment & Processes

LOX demonstration on Taurus II, LH2 demonstrated in test only

Alternate Hydrocarbon Fuels

Demonstration of fuels for rocket applications and green propellants

3–5 Performance characterization Subscale demonstrators, full-scale demonstrators

Alternate Oxidizers Demonstration of alternate oxidiz-ers

3–5 Performance characterization Subscale demonstrators, full-scale demonstrators

Strained Ring Hydro-carbons

Isomers of existing hydrocarbons with novel arrangements of the atoms and increased bond energies, resulting in an expected Isp increase

3 Low-cost, high-yield production. Production R&D, combustion tests, subscale demonstrators, full-scale demonstrators

Gelled Propellants Gelled propellants provide com-parable density impulse to solid propellant systems while delivering the mission flexibility of a liquid system while demonstrating greater operational safety.

2–4 Performance characterization Modeling of systems, subscale demon-strators, full-scale demonstrators

Metalized Propellants Fuels with suspended metal pow-ders or nano particles

2–4 Performance characterization Modeling of systems, subscale demon-strators, full-scale demonstrators

TA01-17DRAFT

2.2.7.3. Air-Breathing Launch Propulsion Systems

Technology invest-ment

description Trl major Challenges Path to Trl6

1.2.6 Fundamental Liquid Propulsion Technologies – Technologies enabling advances in liquid rocket engine launch propulsion including advanced engine design and modeling tools, advanced materials, new nozzle technologies, combustion physics research, and advanced turbomachinery components

Combustion Physics Fundamental physics modeling of combustion processes

N/A Obtaining sufficient test data to an-chor developed models and codes.

Modeling of systems, subscale demon-strators

Advanced Nozzle Concepts

Design, modeling, and demonstra-tion of advanced nozzle concepts

N/A Manufacturing processesMaterials

Modeling of systems, subscale demon-strators

Advanced Design Tools Development and validation of ad-vanced design and modeling tools

N/A Obtaining sufficient test data to anchor predictive analysis models and codes.

Modeling of systems, subscale demon-strators

Propulsion Materials Modeling and demonstration of advanced materials

N/A Manufacturing processesMaterials

Modeling of systems, subscale demon-strators

Advanced Turbomachin-ery Components

Modeling and demonstration of advanced turbomachinery com-ponents

N/A Manufacturing processesMaterials

Modeling of systems, subscale demon-strators

Table 5. Air-Breathing Propulsion System Technology Investments.Technology invest-ment

description Trl major Challenges Path to Trl6

1.3.1 Turbine-Based Combined Cycle (TBCC) – Multiple propulsion modes starting with a turbine-based engine, transitioning with increases in speed to ramjet mode, scramjet mode, and finally to rocket mode

TBCC Flow Path Con-troller

Ensure stable operation of propul-sion system flow paths while maxi-mizing vehicle Isp and thrust

4 Controlling proper fuel/air mixture; control mass and speeds of inlet air to multiple inlets

Conduct tests on flow path-induced thrust fluctuations

TBCC High-Mach # Turbine Acceleration

Operate turbine engines to Mach 4 and pursue Mach 6 turbine ac-celeration

3 Need compressor, combustor, and turbine designs and materials that withstand high temperatures; thrust augmenter designs

Test high-temperature engine compo-nent designs and materials, test Mach 4+ augmenter performance, perform Mach 4 turbine ground and flight tests, investigate cooling to achieve Mach 6 turbine acceleration

TBCC Inlet Optimization Initiate stable flow in multiple-speed inlets (for turbine, ram/scramjets and rockets)

4 Proximity of inlet systems leads to flow coupling effects

Test simultaneous inlet functioning, test thermal choking and positioning of the flow shock structures, test inlet geometries

TBCC Turbine/Scramjet Mode Transition

Maintain vehicle propulsive thrust during sequence of turbine engine shutdown and initiation of ramjet/scramjet combustion

3 Transitioning operation from one propulsion mode to another while maintaining thrust

Verify stable turbine flow path opera-tion leading to stable ramjet/scramjet ignition, test stable turbine shutdown methods, determine safe thermal environment

1.3.2 Rocket-Based Combined Cycle (RBCC) – Multiple propulsion modes starting with a ducted engine (an ejector ramjet) to augment the airflow until the vehicle reaches suitable speeds at which point it transitions to ramjet mode, scramjet mode, and finally to rocket mode

RBCC Ejector Thrust Augmentation

Supply increased mass flow to allow engine to operate at low supersonic speeds

3-4 Providing sufficient entrainment and mixing of air with rocket plume for increased low-speed RBCC performance

Test ejector geometries and map flow field

RBCC Mode Transition Maintain vehicle propulsive thrust during sequence of ejector mode shutdown and initiation of ramjet combustion

3 Transitioning operation from one mode to another while maintaining thrust

Verify ejector flow path operation lead-ing to stable ramjet /scramjet ignition, determine safe thermal environment

RBCC Plug Nozzle Maintain efficiency at a wide range of altitudes

3 Plug nozzle shape and characterizing interaction of plug with flow path

Perform research to determine optimum plug nozzle shapes and map flow proper-ties around nozzle

RBCC Dynamic Inlet/Nozzle Optimization

Initiate stable flow in multiple-speed inlets and nozzles (for ejector, ram/scramjets and rockets)

3-4 Proximity of inlet systems leads to flow coupling effects; nozzle sizing

Test simultaneous inlet functioning, test thermal choking and positioning of the flow shock structures, test inlet and nozzle geometries

1.3.3 Detonation Wave Engines (Open Cycle) – Acceleration achieved by igniting fuel and oxidizer through a series of controlled detonation waves, employ-ing an open cycle where oxidizer is obtained from the atmosphere

Detonation Wave Engine Fuel/Oxidizer Injection and Mixing

Inject and mix fuel and oxidizer at optimum rates and amounts

3–4 Timing of propellant injection and mixing is critical for reactions to occur

Test injector architectures, test mixing methods

TA01-18 DRAFT

Technology invest-ment

description Trl major Challenges Path to Trl6

Detonation Wave Engine Ignition Control

Start detonation reaction in a con-trolled manner

3–4 Controlling ignition; reduce noise; dampen pulsed operation vibration

Test detonation ignition techniques, study noise levels and research methods for reducing noise, develop vibration dampening technologies

Pulsed Detonation Wave Engine

Use detonation waves (in pulsed-mode operation) to combust fuel and oxidizer

3–4 Timing injection, mixing and ignition pulses; reducing vibration and noise

Test timing sequencing, integrate propulsion/ airframe for low- and high-speed flight tests

Continuous Detonation Wave Engine

Use detonation waves (continuous operation) to combust fuel and oxidizer

2-3 Controlling ignition and wave propagation; cooling; reducing inlet flow speeds

Research and test inlet flow speed reduc-tion methods, integrate propulsion/air-frame for low and high-speed flight tests

1.3.4 Turbine Based Jet Engines (Flyback Boosters) – Turbine engines modified to handle the stresses of launch and reentry that are able to fly a launched vehicle back to the launch site

Flyback Engine Alterna-tive Fuels

Demonstrate alternative fuels for commonality with existing rocket propellants

4–5 Ability to provide high energy content; able to absorb heat; thermal stability

Flight test alternative fuels

Flyback Engine Vibra-tion

Reduce potential engine damage during launch

3 Dampening vibration on engine dur-ing high-speed flyback

Develop and flight test vibration damp-ening technologies

Flyback Engine Reduced Fuel Consumption

Reduce amount of fuel needed to operate flyback engine

3-5 Finding fuels with increased energy content; increase efficiency of com-bustion.

Research, develop, and flight test methods to reduce flyback engine fuel consumption

1.3.5 Ramjet/Scramjet Engines (Accelerators) - Ramjets ingest atmospheric air at the engine inlet at high speeds and compresses it; air is then slowed to subsonic speeds, at which point it is combined with fuel for combustion. Scramjets compress and ignite air at supersonic speeds

Ramjet/Scramjet Accel-eration Combustion

Increase ramjet and scramjet com-bustion performance and achieve effective combustion over a wide speed range

3–4 Optimizing timing of injection, mixing, igniting, and burning; main-taining sustained operation with high-combustion temperatures

Data review of previous flight tests and continued flight tests of ramjet/scramjet combustion studies

Alternative Ramjet/ Scramjet Fuels

Research alternative fuels for ramjet and scramjet operation

2–3 High energy content; ability to achieve effective combustion over a wide speed range; ability to heat-sink; thermal stability

Flight test alternative fuels, certify fuels

Reduced Ramjet/ Scramjet Inlet Speeds

Allow ramjets and scramjets to begin operation at lower speeds

2–3 Profile inlet boundary layer and shock interactions; determine lead-ing edge and inlet flow path shapes

Research and test inlet geometries allowing lower inlet speeds, study inlet flow-field physics

High-Temperature Ramjet/Scramjet Seals

Employ seals that survive under high temperatures

3 High-temperature tolerance Research and test seal materials and mechanisms

Lightweight Ramjet/ Sc-ramjet Heat Exchangers

Employ heat exchangers made from lightweight materials

3 Developing efficient and lightweight heat exchangers able to operate un-der ramjet/scramjet flight conditions

Research and test lightweight heat exchangers

Ramjet/Scramjet/Propulsion/ Airframe Integration

Integrate the propulsion geometry with the vehicle airframe

3–4 Designing overall vehicle to combine optimal propulsion performance with most effective airframe size

Review past flight test data and refine propulsion/airframe geometry in contin-ued flight tests

1.3.6 Deeply-Cooled Air Cycles – Cryogenic liquid hydrogen fuel is used to cool or liquefy incoming air from the engine inlet; air is then combusted with the liquid hydrogen to create thrust

Deeply-Cooled Air Cycle Heat Exchangers

Increase efficiency of heat exchang-ers used during deeply-cooled air cycle process

3 Increase heat transfer coefficient; design compact, lightweight heat exchanger

Heat exchanger design, fabrication, verification and flight test

Lightweight and Ef-ficient Air Liquefier

Liquefy air collected from the atmo-sphere to be used as oxidizer

3 Reduce weight of air liquefier system Research and test lightweight materials for air liquefiers

1.3.7 Air Collection & Enrichment Systems (ACES) – Liquid oxygen (LOX) is generated by separating it from the atmospheric air, which allows vehicles to take off without LOX on board, minimizing takeoff weight

Low-Mass Air Extraction Extract air during high-altitude flight

3 Extract adequate amount of air for ACES operation in reasonable amount of time at high altitudes

Low-mass air extraction research, design, fabrication, verification, and flight test

Rotational Fractional Distillation

Generate LOX by the separation and distillation of high pressure air (at its dew point)

4 Efficient distillation operation under g-forces

Create ground demonstrator of rota-tional fractional distillation unit, flight test unit

TA01-19DRAFT

2.2.7.4. Ancillary Propulsion Systems

Technology invest-ment

description Trl major Challenges Path to Trl6

ACES Heat Exchangers Increase efficiency of heat exchang-ers used during air collection and enrichment process

3–4 Increase heat transfer coefficient; design compact lightweight heat exchanger

Heat exchanger design, fabrication, verification and flight test

ACES Integrated System Combining ACES subsystems into an operational system

2–3 Maturing ACES subsystems; perform-ing integrated system analysis

Complete ACES system integration and transient ACES operational analyses; produce integrated system and flight test

1.3.8 Fundamental Air-Breathing Propulsion Technologies – Technologies facilitating air-breathing launch propulsion system development

High-Fidelity Integrated Propulsion Design Software

Develop high-fidelity models and design software for hypersonic propulsion systems

N/A Increasing accuracy and speed of model computations; increasing fidelity of design software

Continued software research, develop-ment, test and validation with hardware systems

High-Temperature Ceramic Composites

Develop materials capable of withstanding high temperatures experienced in hypersonics

N/A Advanced material synthesis; material interaction with extreme environments (e.g., temperature, corrosion); physical and structural property characterization

Research, develop, and test high-temper-ature ceramic composites

Carbon-Carbon Nozzles Develop lightweight, high-temp carbon-carbon based nozzles

N/A Increasing carbon-carbon strength under compression and shock

Research, develop and test carbon-carbon nozzles

Advanced Propulsion Thermal Management

Develop advanced propulsion ther-mal management systems capable of supporting vehicle operation under varied temperature ranges

N/A Designing thermal management systems that can adapt to diverse temperature ranges

Evaluate and test integrated thermal management systems operating under transient and continuous heat and cool-ing loads

Actively Cooled Inlets/Nozzles

Develop techniques for cooling propulsion components using the working fluid

N/A Integrating materials and working fluid without adverse effects to materials, working fluid, or propul-sion system

Evaluate and test active cooling inlet/nozzle concepts

Table 6. Ancillary Propulsion System Technology Investments.Technology invest-ment

description Trl major Challenges Path to Trl6

1.4.1 Auxiliary Control Systems (ACS) – These systems provide roll control for single-engine first stage ascent, as well as full upper-stage attitude control during stage separation and coast using small thrusters for propulsive force to rotate the vehicle about the roll, pitch, and yaw axes.

Low-Cost, High Thrust to Weight Ratio Reaction Control Systems (RCS)

Current RCS mono-prop or bi-prop systems are very costly. New ma-terials and production techniques could reduce thruster cost, as well as reduce the weight of the support systems.

4 Low leakage for extended propellant exposure

Propellant exposure testing, demon-strate new production techniques

Non-Toxic RCS Nontoxic RCS propellants can re-duce ground infrastructure cost and complexity, improve ground safety and operational timelines, as well as potentially reduce flight vehicle sys-tem production costs and improve performance. Work has been done already for various bi-prop alterna-tives like LOX/methane, LOX/LH2, LOX/ethanol, and GOX/methane. Hydroxl Ammonium Nitrate (HAN) and Ammonium Dinitramide (ADN) are promising monopropellant alternatives.

4–5 Propellant material compatibility

Small/lightweight cryogenic lines and valves

Material compatibility testing, demon-strate repeatable, consistent ignition and combustion stability

Composite Overwrap Pressure Vessel (CoPV) advances to reduce stress rupture

Develop understanding of root cause of stress rupture and fine tune design without oversizing the tank. This would permit a reduced safety factor, resulting in lighter weight tanks. Advances in CoPV technol-ogy also could be applied to MPS applications.

2 Material properties understanding Applied research into physical properties and initiation of stress rupture, develop lower weight designs based on this data

TA01-20 DRAFT

Technology invest-ment

description Trl major Challenges Path to Trl6

1.4.2 Main Propulsion Systems (MPS) – Subsystems that provide propellant conditioning and feed, tank pressurization, and purge supply to the engine use insulated lines and components for cryogenic applications

Advanced, Low-Cost Cryogenic and RP Com-ponents

Evolutionary development of robust, low cost fill and drain, recirculation, and engine isolation valves, ducts, recirculation pumps and cryogenic helium regulators for expendable and reusable launch vehicles using materials advances and improved production methods would greatly reduce production costs and improve reliability for reusable applications.

4 Maintaining low mass

Design simplification for production

Design for cost, reliability, and reusabil-ity, demonstrate production capability at reduced cost

1.4.3 Launch Abort Systems – Propulsive systems for pulling spacecraft away from the launch vehicle in the event of a launch failure

Vectorable High-Thrust Abort Motor

High-thrust abort motor designs with vectorable thrust enable im-proved launch abort vehicle control through all flight regimes. High-thrust TVC also requires high slew rate, high slew angle, high thrust (50,000–150,000 lbf) solid propellant motors and associated systems.

4 Development of the high peak power batteries (i.e., thermal bat-teries that would be acceptable to NASA) for TVC use

Demonstrate integration of the TVC system with the motor cases

Adaptive Flight Control Automated flight controls for launch abort vehicles (e.g., at a minimum as an outer loop around a more conventional flight controller) would address the uncertainty inherent in abort scenarios and improve abort system reliability over a wide range of operating and environmental conditions.

2 Lightweight, minimal volume for self contained LAS flight control system

Demonstrate capability of system sized to fit within available LAS constraints

Liquid Propellant Inte-grated Abort System

Liquid propulsion systems capable of providing both the high thrust required for vehicle abort and low thrust required for on-orbit maneu-vering and attitude control from an integrated package.

1 Fast-response, high-pressure, mid-thrust (3,000–5,000 lbf) propulsion systems, with variable thrust/sec (throttleable or pulse modulated) development

Maturation of associated components in-cluding high-pressure tanks, regulators, bi-propellant valves, and the thruster itself are needed

1.4.4 Thrust Vector Control (TVC) Systems – Actuators that adjust the direction to the exhaust gas plume to provide vehicle steering

Non Toxic Turbine Power Units for Hydraulic Pres-surization

Develop replacement for hydrazine-driven hydraulic power units using either nontoxic propellant or a blow-down type system.

4 Integrated vehicle impacts Initial development of options, demon-stration tests

Advanced Actuator Development (EHA, EMA, IAP)

Advance state of the art of electro-hydrostatic and electromechanical actuators as well as an integrated actuator pack¬age for use on a wide range of launch vehicles especially RLVs for simpler, lower cost inte-grated TVC systems.

3 Fault tolerance

Power draw

Demonstrate robust operation with fault tolerance

Corona-proof, Rapid Charge/Discharge High Power Battery & Power Distribution Systems

Advanced actuators will require greater electrical power from a high-voltage, rapid-discharge battery & distribution system. This system must be developed to avoid corona effects during ascent.

3 Lightweight shielding

Robust battery

Provide sufficient environmental testing for shielding development

1.4.5 Health Management & Sensors – Propulsion system instrumentation and associated avionics architecture that monitor propulsion system health

Evolutionary Diagnos-tic/ Prognostic Sensor and Monitoring System Development

Develop advanced sensors for all ancillary applications for use in ground processing and flight to im-prove hardware life as well as fault detection and isolation. Includes cryogenic & hypergolic liquid level sensors, flowmeters, leak detection sensors, extreme environment sen-sors, & rotating machinery sensors using advances in fiber optic, Piezo-electric, Microelectromechanical & nanosensor technology.

3 Extreme environments

Signal processing bandwidth

Environmental testing, demonstrate integrated function with hardware devel-opment

TA01-21DRAFT

2.2.7.5. Unconventional/Other Propulsion Systems

Technology invest-ment

description Trl major Challenges Path to Trl6

Continuously Advance Flight Environments Characterization

Continue to develop, flight qualify, and implement add-on flight in-strumentation (sensors to monitor strain, temperature, vibration, acoustics, etc., along with associated power, data acquisition, and wireless communication technologies for flight environments) that can pro-vide the necessary environmental information to verify, and potentially optimize designs of launch vehicle propulsion systems.

2–3 Extreme environments

Power restrictions

Environmental testing

1.4.6 Pyrotechnic and Separation Systems – Linear-shaped charges or frangible bolts are typically used for stage separation

Fully Redundant Separa-tion Subsystem

Demonstrate, first through ground testing and then later in flight, dual redundancy for stage separation whether the separation subsystem uses a linear shaped charge or a frangible type joint to increase safety.

2–3 Vehicle system interactions due to pyro shock loads

Model system, design prototype, ground test, update model and prototype

Purely mechanical sepa-ration subsystem

Develop minimal weight highly reli-able mechanical stage separation system for medium and large launch vehicles. Eliminating pyrotechnic separation systems would eliminate pyro shock concerns for nearby flight hardware and simplify produc-tion and ground processing.

3–4 Minimizing weight penalty for purely mechanical system and scale-up to large systems

Load requirements, prototype system, lab test, flight test

1.4.7 Fundamental ancillary propulsion technologies basic technologies that would apply to the all the various ancillary systems

Advanced Materials Development

Critical to advances for all ancillary systems. Material improvements advance the state of the art by reducing weight and/or cost.

N/A Material Compatibility Implement advances into component design

High-Fidelity Predic-tive Capabilities for Aerodynamics, Loads & Environments, & Flight Control

Improved models with predictive capability, anchored with appropri-ate test data, would greatly benefit MPS, ACS, TVC, and LAS develop-ment by providing a large reduction in model uncertainty as well as reductions in development time and cost.

N/A Obtaining sufficient test data to an-chor developed models and codes.

Develop and refine codes based on ap-plicable test data

Comprehensive Py-rotechnic Component Modeling Tool

Develop comprehensive pyrotech-nic component computer modeling tool, anchored with testing, to reduce the development cost and schedule impact of new pyrotechnic component designs.

N/A Adequate characterization of com-ponent performance

Generate performance database, de-velop model, anchor with test

Table 7. Unconventional/Other Propulsion System Technology Investments.Technology invest-ment

description Trl major Challenges Path to Trl6

1.5.1 Ground-based Launch Assist – Applying a method of accelerating a vehicle horizontally or vertically to give it a higher initial velocity and to reduce the amount of propellant required to reach orbit

Combustion Gas Cata-pult (Low Speed)

Combustion gas launch assist is a pneumatic hot gas system derived from mature aircraft carrier steam-catapult technology. Assist veloci-ties would range from subsonic to transonic.

3–4 High-volume gas generation capa-bilities. High transient thermal and mechanical stresses. Low main-tenance seals. Vehicle separation dynamics.

Tests to incrementally increase launcher length and velocities, vehicle separation tests

Maglev Catapult (Low Speed)

Magnetic levitation techniques are used to support and accelerate a vehicle for horizontal launch assist. Assist velocities would range from subsonic to transonic.

3–4 Scaling to large vehicle masses. Energy storage and power switching. Vehicle separation dynamics.

Energy storage and power switching R&D, subscale system demo, including sep testing

Hydrogen Gas Gun (Hypervelocity)

A large-bore gun that accelerates a payload/rocket stage along the bar-rel through the rapid expansion of hydrogen gas from a high-pressure reservoir.

3 Hydrogen pressurization. Projectile integrity.

Hydrogen pressurization system design and test, subscale system demo

TA01-22 DRAFT

Technology invest-ment

description Trl major Challenges Path to Trl6

Blast Wave Accelerator (Hypervelocity)

The blast wave accelerator uses rings of high explosives inside a long tube that are sequentially detonated to accelerate a payload/rocket stage.

3 Projectile and launcher integrity. Timing of sequential detonation and detonation uniformity. In-bore stability.

Detonation testing, projectile acoustic tests, subscale system demo

Ram Accelerator (Hypervelocity)

The ram accelerator consists of a long, sealed tube filled with a mixture of fuel and oxidizer, such as hydrogen and oxygen. A projectile resembling the center body of a ramjet is shot into the tube, igniting the mixture and blasting the projec-tile down the tube, which acts like the outer cowling of a ramjet.

3 Erosion of the projectile and tube. Premature fuel detonation in front of the projectile. Greater than Mach 6 in-tube, supersonic combustion. Large, fast-acting valves.

Laboratory experiments at in-tube Mach of 6–10, and ultimately velocities of 6–8 km/s, subscale system demo

Electromagnetic Gun (Hypervelocity)

A railgun consists of a pair of copper rails, mounted in an insulating bar-rel, with the rails connected to a rap-idly switched high current source. An armature on the projectile to be fired completes the circuit, resulting in a magnetic force that drives the projectile down the barrel.

3–4 Power requirements. Structural in-tegrity of projectile and launcher. Rail erosion and life. Energy storage and power switching. Plasma armature performance.

Energy storage and power switching R&D, plasma armature R&D, rail erosion tests, subscale system demo

Mechanical Accelerator (Hypervelocity)

Typified by the Slingatron concept, it consists of a long tube arranged in a spiral pattern which accelerates a small payload to orbital velocity by gyrating the tube assembly in an oscillatory pattern. Acceleration of the payload is by centripetal forces.

3–4 Structural integrity of the system. Friction in the interior of the spiral tube. Projectile integrity.

Structural design, stress and vibration analysis. Testing of techniques to reduce tube friction. Subscale system demo.

1.5.2 Air Launch/Drop Systems – Space launch vehicles carried to the upper atmosphere by a carrier aircraft

Large Subsonic Stage Stage launch vehicle from top or bottom of very large (jumbo jet-class) subsonic carrier aircraft.

5 Increasing aircraft lift capabilities. Stage separation dynamics. Large, twin fuselage configuration.

High-lift device R&D, configuration R&D, separation simulations and subscale testing

Supersonic Stage Stage launch vehicle from carrier aircraft at supersonic speeds.

5 Mated configuration drag. High-q stage separation.

Low-drag config. R&D, subscale sep tests

1.5.3 Space Tether Assist – Space-based tethers using momentum exchange to accelerate payloads from suborbital to orbital velocities, reducing require-ments for launch vehicle ascent performance

Hanging Tether A gravity-gradient stabilized tether that reaches down to the upper atmosphere from orbit (e.g., Sky-hook). Payloads are delivered to the bottom of the tether by a suborbital vehicle, then transported up along the tether and released into orbit.

2–3 Tether life in LEO environment. High-speed tether reel-in and reel-out. Flywheel energy storage. Rapid payload capture mechanism. Robust tether dynamics modeling.

High-speed reel demo, flywheel ground demo, orbital electrodynamic tether propulsion demo, subscale orbit demo, including P/L capture

Rotating Tether A tether that rotates or spins in the plane of its orbital motion (e.g., Rotovator or Bolo). Payloads are delivered to the tether by a subor-bital vehicle and are transferred into orbit by the rotation of the tether and an exchange of momentum.

2–3 Tether life in LEO environment. Reli-able tether deployment. Flywheel energy storage. Rapid payload cap-ture mechanism. Robust modeling of tether dynamics.

Flywheel ground demo, orbital elec-trodynamic tether propulsion demo, sub-scale orbit demo, including P/L capture

1.5.4 Beamed Energy / Energy Addition – Ground-based laser, microwave, or other focused electromagnetic radiation to heat air at the base of a vehicle, or the propellant carried onboard, to produce propulsion at high efficiencies

Microwave/Laser Thermal Rocket

Microwaves or lasers beamed from a ground or space station are directed at a heat exchanger mounted on a vehicle to heat stored propellant and create thrust via a thermal rocket, achieving Isp from 600 to 900 sec.

2–3 Very large power transmitters (GW-class), accurate tracking, efficient energy conversion, and thermal management.

Power beaming and tracking tests, heat exchanger R&D, small-scale flight demo

Laser Lightcraft A pulsed laser from a ground station is used to heat atmospheric air, or onboard propellant, and rapidly expand it against a focused pusher plate on the vehicle, generating thrust.

2–3 Very large power transmitters (GW-class), accurate tracking, efficient energy conversion, and thermal management.

Power beaming and tracking tests, small-scale flight demo, all propulsive modes

MHD-augmented Rocket

Magnetohydrodynamic (MHD) effects can be used to further accel-erate the exhaust products of a con-ventional chemical rocket engine to achieve significantly higher levels of thrust and Isp (1,000 – 2,500 sec).

2–3 Power requirements. Mass efficiency of system components. Thermal management.

Power systems R&D, low-mass compo-nent development and test, ground engine tests

TA01-23DRAFT

3. inTerdePendenCy wiTh oTher TeChnoloGy areaS

The launch vehicle propulsion technology area has many interdependencies and synergies with many of the other technology areas. (If a TA is not listed, no significant interdependency was identi-fied.) Among them are:

In-Space Propulsion – Most of the fundamen-tal tools, rocket propulsion, and nonrocket (teth-er) propulsion systems have direct synergy with the in-space propulsion area. This is particular-ly true for launches from planetary surfaces, in-

cluding bodies with atmospheres, both for robot-ic sample return and for safe and assured return of humans. Many of the technology challenges fac-ing launch vehicle propulsion systems are com-mon to the ones facing this TA.

Space Power and Energy Storage Systems – There are several propulsion systems like beamed energy that use high-power electrical storage and distribution systems, which are synergistic with this TA. Nuclear propulsion systems are also con-sidered synergistic with this TA in the area of pow-er generation.

Technology invest-ment

description Trl major Challenges Path to Trl6

1.5.5 Nuclear - Using nuclear fission or fusion reactions for high propulsive performance.

Advanced Solid Core Fission NTR

A nuclear thermal rocket (NTR) that uses an advanced solid-core nuclear fission reactor. The reactor employs fine alloy fibers arranged in a lattice for greatly improved heat transfer to the propellant and increased Isp (>1,000 sec) with reduced mass.

2 Lightweight, robust, high-tempera-ture core with low pressure drop and high surface area. Radiation shield-ing. Accident hazard containment.

Core material and manufacturing R&D, rad shielding R&D, component tests, ground engine tests

Liquid & Gaseous Core Fission NTR

Thermal rockets that use liquid- or gaseous-core nuclear fission reac-tors. These would operate at very high temperatures, potentially enabling Isp of 3,000–5,000 sec.

2 Nuclear criticality, radiant heat transfer, and fuel containment. Radiation shielding. Accident hazard containment.

Analysis and lab testing, rad shielding R&D, component design and testing, sys grnd demo

Fusion NTR A thermal rocket that uses a fusion reactor. Concepts for achieving clean aneutronic fusion include Inertial Electrostatic Confinement, Inertial Electrodynamic Fusion, and Dense Plasma Focus. Performance is generally similar to fission NTR.

2 Device size to achieve power break-even. Control of ion and electron feeds. Structure and cooling. Drive current/ voltage. Magnetic field drive (for IEF).

Scaled-up reactor tests, continuous reac-tor operations demo, component design and testing, sys grnd demo

External Pulsed Plasma External pulses generated by successive detonations of nuclear material are used to generate propulsion by the action of plasma expanding against a pusher plate at the rear of the vehicle. (Isp of 5,000–10,000 sec).

2 Type of pulse unit, its degree of collimation, detonation position and fissile bum-up fraction. Pulse unit safety and loading. Pusher plate-plasma interaction.

Pulse unit R&D, detonation testing, plasma interaction tests, subscale flight demo

Low-Energy Nuclear Reactions NTR

A thermal rocket that uses a reac-tor that operates on Low Energy Nuclear Reactions (LENR), a form of “cold fusion.” Performance would be similar to other NTR approaches, but without the radiation hazards.

1 Development and validation of underlying LENR predictive theory. Demonstration of controlled reac-tions.

LENR process research, experimentally initiate and control LENR, component design and testing, sys grnd demo

Nuclear-based Com-bined Cycle

The energy from nuclear reactions is applied in a combined cycle propul-sion system with both air-breathing and rocket modes of operation. Spe-cific impulse values in air-breathing mode are essentially infinite.

2 Challenges are similar to those of conventional TBCC and RBCC systems and advanced NTR, but include integration of a nuclear reactor into an air-breathing flow path.

Analysis and lab testing (including wind tunnel tests), rad shielding R&D, compo-nent design and testing, sys grnd demo, flight demo

1.5.6 High Energy Density Materials/Propellants – Propellants or materials that contain considerably higher stored energy per mass than conventional chemical propellants

Polynitrogen New liquid or solid compounds of nitrogen, such as N4 or N8, which release very high energy upon decomposition into N2 molecules, potentially enabling Isp of 350–500 sec.

2 Stability/shock sensitivity, produc-tion, and storage.

Formulation R&D, production R&D, stability tests, propulsion demos

Nanopropellants Propellants with embedded nanoscale particles of combustible material (e.g. aluminum powder), providing greater reactive surface area and energy.

2 Controlled energy release. Consis-tently reproducible properties.

Production R&D, combustion/ stability tests, propulsion demos

Atomic and Metastable Very high-energy propellants that contain atomic free-radicals or metastable forms of molecules, such as atomic hydrogen, metasta-ble helium, and metallic hydrogen. Potential for Isp > 2,000 sec.

2 Stability/shock sensitivity, produc-tion, and storage.

Production R&D, energy release and stability tests, propulsion demos

TA01-24 DRAFT

Robotics, Tele-Robotics, and Autonomous Systems – Fault detection, isolation, and recovery capabilities as well as prognostic/diagnostic capa-bilities in this TA are synergistic with IVHM tech-nology.

Scientific Instruments, Observatories, and Sensor Systems – Sensor technologies related to cryogenic or high-temperature applications are highlighted in this TA and the LPSTA and are synergistic.

Entry, Descent, and Landing Systems – Tech-nologies for reaction control systems and reentry propulsion are synergistic with this technical area.

Nanotechnology – Many areas of nanotechnol-ogy, including low-weight, high-strength and/or high-temperature materials, sensors, propellants, coatings, and insulation directly feed into launch vehicle propulsion applications. This is an interde-pendent technical area.

Modeling, Simulation, Information Technol-ogy, and Processing – We share interdependency with this TA, as fundamental design and analysis tools are needed for engine component and sys-tem development and test.

Materials, Structural and Mechanical Sys-tems, and Manufacturing – Many areas of this TA, including low-weight, high-strength, and/or high-temperature materials, sensors, coatings, and insulation as well as manufacturing process-es would directly feed into launch vehicle propul-sion applications. This is an interdependent tech-nical area.

Ground and Launch Systems Processing – There are both synergies and interdependencies between LPSTA and this TA. Sensor development for ground applications is synergistic with propul-sion applications particularly for cryogenic sys-tems. The LPSTA and this TA are interdependent regarding IVHM technology development.

Thermal Management Systems – In general, thermal management is a critical need for launch propulsion systems. While we do share synergy with this TA regarding cryogenic insulation tech-nologies, propulsion systems could share inter-dependency with this TA if they broadened their scope to include propulsion-specific applications.

4. PoSSiBle BeneFiTS To oTher naTional needS

In addition to supporting NASA goals for space exploration and the achievement of routine, low cost access to space, the advancement of launch propulsion technologies supports national needs as a whole. These needs include those of oth-er government agencies, such as the military, the national security community, and NOAA, which would benefit greatly from the reduced costs, improved reliability, and greater utility of new launch systems enabled through advanced propul-sion technology. Similarly, the success and com-petitiveness of the commercial launch industry would be greatly enhanced through the creation of more efficient and cost effective launch propul-sion systems. The President has tasked NASA with helping the nation sustain and expand its world leadership in aerospace technology, which in turn provides many spinoffs to other industries and a major opportunity to reinvigorate STEM educa-tion. The President’s current budget proposal also emphasizes developing the commercial launch in-dustry. This could lead to the establishment of new, emerging markets for an active and aggres-sive entrepreneurial launch industry.

Over the last decade and a half, the U.S. aero-space industry has been significantly impacted by the lack of investment in launch propulsion tech-nologies. This has caused the U.S. to lose several key technology capabilities that enable access to space. Some critical aspects of our ability to ac-cess space rely on foreign suppliers, e.g., ORSC engines, which put restrictions on the use of their supplied technologies. These restrictions have a significant impact on national security and de-fense, and they can only be addressed by creating a national supply base for these critical compo-nents and technologies. Thus, any investment in propulsion technology will help to offset this loss, will help establish a basis on which to reinvigo-rate the fundamental LPSTA capability, and will re-grow technological “seed corn” for the future.

TA01-25DRAFT

aCronymSACES Air Collection and Enrichment SystemsACS Auxiliary Control SystemAdv/Advcd AdvancedAIAA American Institute of Aeronautics and AstronauticsAlt. AlternativeAMPM Agency Mission Planning ManifestADN Ammonium DinitramideAP Ammonium PerchlorateAPIO Advanced Planning and Integration OfficeARC Ames Research CenterARMD Aeronautics Research Mission DirectorateATP Authority to ProceedCAD Computer Aided DesignCC Closed CycleCCDev Commercial Crew DevelopmentCFD Computational Fluid DynamicsCH4 MethaneCoPV Composite Overwrap Pressure VesselCOTS Commercial Orbital Transportation ServicesCRAI Capability, Requirements, Analysis, and Integration Cyc CycleDCR Design Certification ReviewDemo DemonstrationDGLR Deutschen Geselleschaft für Luft- und Raumfahrt (German Scientific Society for Aeronautics)DRA Design Reference ArchitectureDLR Deutschen Zentrums für Luft- und Raumfahrt (German Aerospace Center)DRM Design Reference MissionDyn DynamicECLS Environmental Control and Life SupportEELV Evolved Expendable Launch VehicleEff EfficientEHA Electrohydrostatic ActuatorEHS Environmental Health SystemELV Expendable Launch VehicleEMA Electromechanical ActuatorEng EngineESMD Exploration Systems Mission DirectorateETO Earth to OrbitFlt FlightFOM Figure of MeritGG Gas GeneratorGOX Gaseous OxygenGrnd GroundGW GigawattHAN Hydroxyl Ammonium NitrateHC HydrocarbonHEDM High-Energy Density MaterialHEFT Human Exploration Framework Team

HLPT Heavy Lift Propulsion TechnologyHLV Heavy Lift VehicleHTPB Hydroxyl-Terminated PolybutadieneHX Heat ExchangerHyp HypersonicIAP Integrated Actuator PackageIEC Inertial Electrostatic ConfinementIEF Inertial Electrodynamic FusionIHPRPT Integrated High Payoff Rocket Propulsion Technology IPT Integrated Product TeamIsp Specific ImpulseISS International Space StationIVHM Integrated Vehicle Health ManagementJSC Johnson Space Centerk Thousandkg Kilogramklbf Thousands of pounds of forceKSC Kennedy Space CenterLAS Launch Abort Systemlbf Pounds of forceLCC Life Cycle CostLENR Low-Energy Nuclear ReactionsLEO Low-Earth OrbitLH2 Liquid HydrogenLOX Liquid OxygenLPSTA Launch Propulsion Systems Technology AreaLST Life Support TechnologiesLt. Wt. Light WeightMgmt ManagementMHD MagnetohydrodynamicsMlbf Millions of pounds of forceMPS Main Propulsion SystemMSFC Marshall Spaceflight CenterN2 NitrogenN/A Not ApplicableNAI National Aerospace InitiativeNEO Near Earth ObjectNGLT Next Generation Launch TechnologyNIA (Boeing) National Institute of AerospaceNRC National Research CouncilNTR Nuclear Thermal RocketOC Open CycleOCT Office of the Chief TechnologistOMB Office of Management and BudgetOp OperationalOpt OptionORSC Oxygen Rich Staged CombustionPBAN Polybutadiene AcrylonitrileProp PropellantProto PrototypePt. PointRad Radiation

TA01-26 DRAFT

RBCC Rocket Based Combined CycleRBS Reusable Booster SystemRCS Reaction Control SystemR&D Research and DevelopmentRLV Reusable Launch VehicleRP Rocket Propellant (hydrocarbon-based)RSRM Reusable Solid Rocket Motorsec. SecondsSHLV Super Heavy Lift VehicleSLI Space Launch InitiativeSMD Science Mission DirectorateSOMD Space Operations Mission DirectorateSRB Solid Rocket BoosterSRM Solid Rocket MotorSSME Space Shuttle Main EngineS/W SoftwareSys SystemT Metric tonTA Technology AreaTABS Technology Area Breakdown ScheduleTBCC Turbine Based Combined CycleTDRS Tracking and Data Relay SatelliteTech Dev Technology DevelopmentTherm ThermalTRL Technology Readiness LevelTVC Thrust Vector ControlT/W Thrust to Weight (ratio)U.S. United StatesU/S Upper Stage

aCknowledGemenTSThe NASA technology area draft roadmaps were

developed with the support and guidance from the Office of the Chief Technologist. In addition to the primary authors, major contributors for the TA01 roadmap included the OCT TA01 Road-mapping POC, James Reuther; the reviewers pro-vided by the NASA Center Chief Technologists and NASA Mission Directorate representatives, and the following individuals: Bart Leahy, George Story and Jonathan Jones.

TA01-27DRAFT

This page is intentionally left blank

TA01-28 DRAFT

November 2010

National Aeronautics and Space Administration

NASA HeadquartersWashington, DC 20546

www.nasa.gov